Liquid atomization provides many advantages in various fields. One example of a field where the atomization of liquids increases the quality of products is the pharmaceutical industry. When a medicine is to be administered by spray, the size of each sprayed drop is a crucial factor regarding the efficiency of the medicine, since as the size of each drop is smaller, the medicine is better distributed on a surface, and can be absorbed evenly and more efficiently.
An even and high-quality distribution of materials can also be applied in the cosmetic field, where the spreading of a material needs to be as uniform as possible. It can also apply to sun-screening products for example, and of course in many other fields.
Another example of a field where liquid atomization can improve results is mechanic engineering, particularly regarding engines that operate by fuel. The fuel is injected as a spray of droplets into an engine combustion chamber, and smaller droplets provide more effective combustion as they have more developed surface for chemical reactions and transport phenomena, and thus the engine performance increases.
There are drop size reducing devices and methods that face the same main problem that needs to be solved—when the size of drops is reduced, the flow sufficiency decreases. This is because in most of the atomizing devices the droplets flow rate increases with the size of the orifice through which liquid is pushed to generate the droplets. Smaller orifices result in smaller droplets but reduce their flow rate.
Many known methods for liquid atomization use a device that functions as a centrifuge, which releases liquid through at least one nozzle while rotating. The rotation speed of such device and the size of the nozzle will determine the size of the drops of the released liquid. Apart from the main known problem of flow sufficiency, this method also suffers from the problem of lack of uniformity. The size of the drops, according to this method, is in direct relation to the speed of rotation of the device, and until the device reaches its desired speed, the size of the drops changes as long as the speed of rotation keeps changing. Moreover, the size distribution of droplets may range from very small to big droplets for the same speed of rotation.
Another example of a known method is the use of ultrasonic waves. When a liquid material is placed on a piezoelectric surface that is connected to electrodes, an electric voltage through the electrodes causes the piezoelectric surface to vibrate, and when the vibration is powerful enough to overcome the tension of the liquid surface, it forms the atomized drops. Although this method allows obtaining droplets of less than ten microns, it suffers from low droplet flow rates and high energy consumption.
Thus, the major drawbacks of the current methods for production of micron and submicron droplets include high atomization energy, high temperature and boiling of liquids, low atomization flow rates, wide distribution of droplet sizes, and poor scalability with low flexibility and controllability; moreover, sensitive materials, such as organic, pharmaceutical and biological, can be damaged by high temperatures or boiling, pressures, electric and/or magnetic fields and ultrasonic waves. Specific costs of atomization of submicron droplets, namely expenses on atomization per effective atomization flow rate, are thus too high. It is therefore an object of the invention to provide method and a device for producing atomized liquid with a relatively small size of drops, which overcomes the drawbacks of the prior art.
It is another object of the invention to provide a liquid atomizing device that is easily operated and easily maintained.
It is also an object of the invention to provide a low-cost liquid atomization system.
It is further an object of the invention to provide a liquid atomization method with a relatively low energy consumption.
Other objects and advantages of the invention will become apparent as the description proceeds.